The invention relates to a railway house car and particularly to railway box cars provided with so-called "sliding doors". The term "sliding doors" includes doors movable down a track on rollers. Three important considerations in sliding doors are their ability to give a tight water and light seal, their ability to withstand damage during loading and unloading operations and their simplicity and ease of operation.
Some prior art roller lift doors have obtained the lower seal by setting the lower edge of the door directly on a track when the door is in the closed position and providing a force-multiplying, lifting mechanism to force rollers out of openings in the lower edges and lift the door edge from the track to accomplish movement of the door along the track. Other prior art doors have been mounted on rollers and latched in position and provided with a sealing projection extending downwardly between the track and the car side.
A car which sits with the lower edge of the door on the track creates an excellent seal but heretofor has required an elaborate mechanical lifting mechanism. These types of doors did provide an advantage that the track could be sealed against the car side throughout its length, which is not the case where a sealing projection is needed between the track and the car side. In the novel structure of the invention, in addition to the improved seal by having the track secured throughout its length to the car side, it is not possible for the track to be forced inwardly toward the car side to wedge and clamp a downwardly projecting sealing portion of the door as is the case where the track is separated from the car side along its length and a sealing projection provided.
Accordingly, the instant invention provides a door which seals on its lower edge but does not require an elaborate lifting mechanism, yet retains an advantage that the track may be sealed throughout its length along the car side thus giving an excellent water and light seal of reduced maintenance requirement over that of the prior art.